• 한국군사과학기술학회지
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• 제5권1호
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• pp.37-44
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• 2002

An echo signal in the active sonar using a high frequency is mainly formed of a specular reflection from the surface of an object along with several equivalent scatter inside, which are characterized by the spatial distribution of the highlights on the object. This thesis proposed a model in which the synthesized echo signal can be expressed as a distributed simulated target. The proposed model is obtained after composing a signal based on the movement of highlights relative to the aspect angle from the discontinuous point of an external hull with a strong reflection from a spheroid underwater target. Because the proposed algorithm includes a synthesis of the signals related to the highlight spacial distribution, it can be applied to all kinds of systems used at a short range, and similar results were obtained to the actual measured results of all reflected signals in previous literature referring to the irregular factor application of an envelope.

• 한국항만학회지
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• 제5권1호
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• pp.71-81
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• 1991

This study deals with the analytical and numerical solution for the combined wave reflection and diffraction near the impermeable rigid upright breakwater, subject to the excitation of a plane simple harmonic wave coming from infinity. Three cases are presented : a) the analytical solution near a thin semi-infinite breakwater, b) the analytical solution near the semi-infinite breakwaters of arbitrary edge angles, $30^{\circ},\;45^{\circ},\;and\;90^{\circ}$, c) the numerical solution near a detached thin breakwater the results are presented in amplification factor and wave height diagrams. Moreover, the amplification factors near the structure(2 wavelength before and behind the structure) are compared for the given cases. A finite difference technique for the numerical solution was applied to the integral equation obtained for the wave potential.

• 대한기계학회논문집A
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• 제21권1호
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• pp.1-11
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• 1997

Austomated visual inspection(AVI) capability has become an important key component in the automated manufacturing system. In such a visual inspection system an intensity(or color) image of a scene is quickly affected by optical property of objects, condition and roughness of surface, lens and filters, image sensor property and lighting system. In particular, the lighting system disign is the most important factor, since it affects overall performance of the visual system. For fast and cheap automated visual inspection system it is important to obtain the good image quality which results from careful attention to the design of the lighting system. In this paper, the lighting subsystem of AVI system is analysed for the inspection of printed circuit board(PCB) patterns. The spectral reflectance of materials, which are composed of PCB, is measured for choosing the light source. The reflection property is theoretically obtained by a reflection model and also obtained by experiments which measure intensity with varying the viewing direction of image sensor and the lighting direction of illuminator. The illumination uniformity of a ring-type illuminator. The lighting system is designed based upon the experimental results and theoretial analysis.

• 한국전기전자재료학회논문지
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• 제31권3호
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• pp.182-187
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• 2018

In this study, 20.8% of a p-type Si bifacial solar cell was used to develop a photovoltaic (PV) module to obtain the maximum power under a limited installation area. The transparent back sheet material was replaced during fabrication with a white one, which is opaque in commercial products. This is very beneficial for the generation of more electricity, owing to the additional power generation via absorption of light from the rear side. A new model is suggested herein to predict the power of the bifacial PV module by considering the backside reflections from the roof and/or environment. This model considers not only the frontside reflection, but also the nonuniformity of the backside light sources. Theoretical predictions were compared to experimental data to prove the validity of this model, the error range for which ranged from 0.32% to 8.49%. Especially, under $700W/m^2$, the error rate was as low as 2.25%. This work could provide theoretical and experimental bases for application to a distributed and microgrid network.

• The Journal of the Acoustical Society of Korea
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• 제21권4E호
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• pp.164-169
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• 2002

This paper proposes a hybrid method for vibration analysis in the medium to high frequency ranges using Power Flow Analysis (PFA) algorithm and Statistical Energy Analysis (SEA) coupling concepts. The main part of the developed method is the application of coupling loss factor (CLF) suggested in SEA to the power transmission, reflection coefficients in PI' A boundary conditions. The developed hybrid method shows very promising results with regard to the applications for the various damping loss factors in wide frequency ranges. And also this paper presents the applied results of Power Flow Finite Element Method (PFFEM) by forming the new joint element matrix with CLF to analyze the various plate structures in shape. The analytical results of automobile, complex plate structures show good agreement with those of PFFEM using the PFA coefficients.

• 한국음향학회지
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• 제21권4호
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• pp.164-164
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• 2002

This paper proposes a hybrid method for vibration analysis in the medium to high frequency ranges using Power Flow Analysis (PFA) algorithm and Statistical Energy Analysis (SEA) coupling concepts. The main part of the developed method is the application of coupling loss factor (CLF) suggested in SEA to the power transmission, reflection coefficients in PI' A boundary conditions. The developed hybrid method shows very promising results with regard to the applications for the various damping loss factors in wide frequency ranges. And also this paper presents the applied results of Power Flow Finite Element Method (PFFEM) by forming the new joint element matrix with CLF to analyze the various plate structures in shape. The analytical results of automobile, complex plate structures show good agreement with those of PFFEM using the PFA coefficients.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.432-435
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• 2007

In this paper, a dual band microstrip patch Antenna is designed for RFID Application. The antenna shows a good performance at the frequencies, 900MHz and 2.45GHz for the radiation characteristics and input impedance matching, as well. The reflection factor is lower than -25dB and a good directivity higher than 5dB is achieved for both frequency.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.722-729
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• 2010

Deciding peak-time demand will be most important factor to decide facilities' capacity of complex transfer centers. Concentration of demand is growing more and more in urban railroad that has 3 minutes headway by using MOE of 15 minutes demand. It is far from reality. Moreover there are various demand and reflection of business facilities' demand and commerce facilities' demand is being requested in complex transfer centers. This study focused on it and suggested demand calculation method about facility design of complex transfer centers.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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• pp.240-246
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• 1999

This parer proposes fuzzy reasoning algorithm for improvement in Zonal Cavity Method that is difficult to calculate average illumination without lighting scope and reflection factor so on. This parer use fuzzy reasoning algorithm for maintainment of the best illumination in spite of some variation those are influenced of room illumination and cut down the difficult to be calculated used Zonal Cavity Method.

• 한국산학기술학회논문지
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• 제15권12호
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• pp.7324-7330
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• 2014

미약한 광원 및 조명이 존재하는 환경에서 획득된 저조도 영상에는 많은 색 왜곡이 발생한다. 이러한 색 왜곡은 해당 비전 시스템의 성능 저하를 발생시킬 수 있는 원인이 된다. 따라서 저조도 영상의 원래 색을 찾는 과정은 비전 시스템의 성능 향상을 위한 중요한 과정이다. 이를 위해 본 논문에서는 저조도 영상을 대상으로 한 이색도 반사 모델 기반의 색 복원 기법을 제안한다. 제안한 기법은 이색도 반사 모델을 기반으로 저조도 영상을 확산 반사와 정반사의 영향을 받는 영역으로 구분한다. 이후 각 영역에 미치는 조명 효과를 제거하기 위하여 grey world 기법과 MSRCR 기법을 적용한다. 마지막으로, 두 기법을 적용하여 생성된 결과 영상에 대해 위치별 가중치를 이용하여 두 영상을 조합하여 최종 결과 영상을 생성한다. 본 논문에서는 성능 평가를 위하여 저조도 합성 영상을 사용하였고, 유클리드 거리 및 각 오차를 성능 평가 요소로 활용하였다. 또한 기존에 연구되었던 다양한 기법과의 성능 비교를 수행하여 성능 평가의 객관성을 확보하였다. 다양한 영상 셋을 이용한 실험에서 제안한 기법은 기존의 기법들에 비해 두 성능 평가요소 관점에서 GTD 영상에 가까운 색 복원이 가능함을 보였다.